47 lines
1.6 KiB
Diff
47 lines
1.6 KiB
Diff
From: Mikulas Patocka <mpatocka@redhat.com>
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Date: Mon, 31 Oct 2011 17:08:57 -0700
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Subject: [PATCH] vmscan: fix shrinker callback bug in fs/super.c
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commit 09f363c7363eb10cfb4b82094bd7064e5608258b upstream.
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The callback must not return -1 when nr_to_scan is zero. Fix the bug in
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fs/super.c and add this requirement to the callback specification.
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Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
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Cc: Dave Chinner <david@fromorbit.com>
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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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fs/super.c | 2 +-
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include/linux/shrinker.h | 1 +
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2 files changed, 2 insertions(+), 1 deletions(-)
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diff --git a/fs/super.c b/fs/super.c
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index 3f56a26..32a81f3 100644
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--- a/fs/super.c
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+++ b/fs/super.c
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@@ -61,7 +61,7 @@ static int prune_super(struct shrinker *shrink, struct shrink_control *sc)
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return -1;
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if (!grab_super_passive(sb))
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- return -1;
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+ return !sc->nr_to_scan ? 0 : -1;
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if (sb->s_op && sb->s_op->nr_cached_objects)
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fs_objects = sb->s_op->nr_cached_objects(sb);
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diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
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index 790651b..a83833a 100644
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--- a/include/linux/shrinker.h
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+++ b/include/linux/shrinker.h
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@@ -20,6 +20,7 @@ struct shrink_control {
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* 'nr_to_scan' entries and attempt to free them up. It should return
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* the number of objects which remain in the cache. If it returns -1, it means
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* it cannot do any scanning at this time (eg. there is a risk of deadlock).
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+ * The callback must not return -1 if nr_to_scan is zero.
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*
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* The 'gfpmask' refers to the allocation we are currently trying to
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* fulfil.
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--
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1.7.7.2
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